It would be a nice historical touch to identify those few special units capable of executing a gas attack. A new Special Ability icon could be implemented to indicate a units ability to employ gas. The use of the various Combat Related Decisions employing Gas should be limited to provinces where an attacking Engineer (Pioneers for the Germans and French) or heavy artillery unit with a ‘Gas Capable’ icon is located. Additional unit types incorporating this ability may be need to be made available for construction once gas weapons are available.